Author Topic: Chris's Marion 91 Steam Shovel  (Read 300325 times)

Offline crueby

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Re: Chris's Marion 91 Steam Shovel
« Reply #3690 on: April 21, 2019, 09:03:20 PM »
Got things assembled again on the first engine, all the links are moving well now, and it wants to run, but doesn't quite yet. Been doing some tweaking on the valve positions, and took the end caps off to see exactly when the pressure is being sent to the cylinders - I think I need to do some adjustments to the size of the chambers in the valves, they were left a bit narrow to allow for fine tuning, and they need to be opened up just a bit in a couple places to get the span across ports working better. Getting close!

Offline crueby

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Re: Chris's Marion 91 Steam Shovel
« Reply #3691 on: April 22, 2019, 12:10:05 AM »
A whole bunch more tweaking, setting, valve slider grinding, adjusting nut slot filing, fettling, fitting, and general farting around, and I got the engine to start moving again! Turns out one of the passages in the right cylinder slider was plugged with chips/oil, and the left slider adjusting nut slot was too shallow, and the throttle slider nut slot was too thin so it was lifting.... All conspired to cause leaks past the valves so not much pressure to the cylinders.
 :wallbang:
Got all that sorted out, with many rounds of taking the steam chest off and on...
 :insane:
And then, there was much rejoicing!

First sign of life was when this happened - it is running, but very jerky, so the timing was off a little (the eccentrics are machined in, so the only timing adjustment is centering on the valve sliders).
A half turn on the valve rod on the left cylinder, and it got a lot smoother:
Stopped to retighten the shoulder bolts on the levers (they are not loctited yet, so they tend to back out during a run), adjusted the pressure a bit, and

Much better!  :cartwheel:   Oh, and sorry for fuzzy videos, forgot that this camera does not focus all that close in video mode, after it has had some more tuning (not today, going to sit back and admire it for a while!) will get out the tripod, clamp it down, and take more video. The throttle lever is not hooked up at the moment, getting the bolt in for that is a pain in the elf muffin, so I wont hook that up till I am more sure that I dont need to take the steam chest off again.
Here it is running slower, still has a leak past one of the sliders that can be heard when it stops, need to chase that down. In the middle where the camera gets close in (and fuzzier) is where I am reaching under the table to change the pressure on the compressor, changing speed a bit.

And one more run for the elves who were off watching tv (lazy little so and sos) during the work all afternoon

Bottom line: yes this design really DOES work!   :whoohoo:   The throttle is too sensitive, want to extend the v-shape of the slot out a bit, may need a new slider for that. I did test, and the reverse direction works the same, so that part is proven too. I figured it SHOULD work, since Marion did it successfully, but my version is modified a bit from thiers, so there was that nagging thought from that change.

Time for chocolate chip cookies!
 :cheers: :cheers:

Offline crueby

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Re: Chris's Marion 91 Steam Shovel
« Reply #3692 on: April 22, 2019, 12:13:16 AM »
Oh, and once the first engine is tuned fully, then I get to do it two more times on the others!   :facepalm2:   They should go quicker based on the learnings from this one, at least. Later on I get to build one more for the steering of the rear tracks - that should be easier since it is 30% smaller.... um... wait...   :insane:    :paranoia:

Offline Don1966

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Re: Chris's Marion 91 Steam Shovel
« Reply #3693 on: April 22, 2019, 12:21:47 AM »
Awesome Dog and thatís sweeter then a bowl of honey.... :pinkelephant:........oh and did I say ........I......._like........ :Love:



 :drinking-41:
Don

Offline Ye-Ole Steam Dude

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Re: Chris's Marion 91 Steam Shovel
« Reply #3694 on: April 22, 2019, 01:06:15 AM »
Hello Chris,


Congratulations, quite an achievement to build such a complex engine on that scale. Sounds strong and smooth at even the higher RPM. Great videos also  :ThumbsUp:

Have a great day,
Thomas

Offline Brian Rupnow

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Re: Chris's Marion 91 Steam Shovel
« Reply #3695 on: April 22, 2019, 01:35:23 AM »
Great stuff, Chris. Neat looking flywheel too----

Offline crueby

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Re: Chris's Marion 91 Steam Shovel
« Reply #3696 on: April 22, 2019, 01:39:24 AM »
Great stuff, Chris. Neat looking flywheel too----
Thanks Brian!  That flywheel is a Unimat leftover from years ago, no spikes but easy to spin!

Offline Art K

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Re: Chris's Marion 91 Steam Shovel
« Reply #3697 on: April 22, 2019, 03:48:17 AM »
Chris,
Runs like a top! and that's a good thing. So let me get this right, you only need to do this 5 more times?
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Online Kim

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Re: Chris's Marion 91 Steam Shovel
« Reply #3698 on: April 22, 2019, 05:50:34 AM »
Congratulations, Chris!  That's very exciting!  :cartwheel:

There's a TON of work in that engine, and to see it finally come to life has got to be a pretty good feeling :)

Kim

Offline Firebird

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Re: Chris's Marion 91 Steam Shovel
« Reply #3699 on: April 22, 2019, 09:06:04 AM »
Hi

B E A UTIFUL  :ThumbsUp:

Cheers

Rich 

Online Steamer5

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Re: Chris's Marion 91 Steam Shovel
« Reply #3700 on: April 22, 2019, 09:49:16 AM »
We all knew you.....errr the elves......could do it!

Well done! Looking & sounding good as well.

Cheers Kerrin
Get excited and make something!

Offline scc

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Re: Chris's Marion 91 Steam Shovel
« Reply #3701 on: April 22, 2019, 10:37:20 AM »
Another excellent result from Chris ( & Co)  Definitely cookies all round :ThumbsUp:                 Terry

Offline cnr6400

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Re: Chris's Marion 91 Steam Shovel
« Reply #3702 on: April 22, 2019, 01:27:05 PM »
Videos were great Chris! Congratulations on the first runner!  :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:

Adjusting a progressive throttle slot is tricky the smaller the engine is, and the shorter the linkage throw is. You may also find the throttle's performance is very different on steam than air. It's that damned physics again...... :insane:

What I have noticed watching operators of full size Erie shovels is that they tend to make full-on full-off type of control movements for the engines rather than easing them to start. This was important for operating costs when the shovels were used for earning a living. But one veteran operator at a show also told me that it was important for keeping condensation flowing out of the cylinders and getting enough oil in, which is why he still did it, at shows nowadays. Just food for thought. :cheers:

Offline crueby

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Re: Chris's Marion 91 Steam Shovel
« Reply #3703 on: April 22, 2019, 03:31:00 PM »
Thanks everyone, its a relief and big smile to see the first one running now! I took a look for the air leak I am hearing, appears to be the right cylinder, think I must have taken the piston ring groove down just a milli-gnats-hair too far and air is blowing past the piston. So, will pull that one and give it one or two wraps of teflon tape under the o-ring to bulk it back out again, should sort it out.


Art - not that bad, need to time/tune one more for the model, and the spare one that I made for separate display (both were built at the same time as this one). Then, there is the smaller version for the steering gear to build - I think that I may take a break on the engines and work on the boiler or cab for a while first! Those are the only remaining subsystems on the model after the slew/crowd engines - sounds like not much but they will be a lot!

CNR - that makes sense, those guys were probably paid by the ton moved. I have a DVD of Marion shovels in use that I got from the HCEA store, its surprising to see something this big doing 3 or 4 scoops per minute from ground to  rail car (the crew around the cars were dodging out of the way!) At the logging museum in Maine, they always keep the drain cocks on the cylinders open while staionary, and close them slowly after several revs getting under way - as I recall they still keep them cracked open a bit, they would rather waste a little steam than crack a cylinder.
Thanks all for following along and helping out with questions/tips!   :cheers: :cheers: :cheers:

Offline crueby

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Re: Chris's Marion 91 Steam Shovel
« Reply #3704 on: April 22, 2019, 04:58:12 PM »
And even more celebration - pulled the cylinder off so I could get to the piston rings, and put a single layer of teflon plumbers tape under the o-rings to bulk them out just that little bit more. Now the huige air leak is gone, and it is running down to a nice slow speed on much less pressure!   :whoohoo: Also tested with the throttle a bit, it can speed up/slow down the revs, and the reverse/forward is functional just fine too.
Here is a short video of it running this morning (also found the setting in the camera for close up focus in video mode, so it should be sharper too)
:pinkelephant:    :cartwheel:
Next I'll put a little blue loctite on the shoulder bolt threads to keep them from backing out every 30 seconds of running, and get some oil on the shoulders sections. There is a film of oil in the cylinders already. After that is set, I'll get out the tripod and do a longer run with throttle, then can start tuning the other two engines.
Much rejoicing, time to take the elves out for lunch!   :LickLips: